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Discussion Starter · #1 ·
I searched to find an area that was fitting for this question, and this is the best I could think of. I just got a B&O beogram rx turntable that I bought online. I don't have a manual, but there's two cords coming from the back of the unit. One looks like a standard stereo cable (I know records are mono), with on gray RCA plug and one Black RCA plug. Then there's a black wire that hase a red "C" connector- like the old television hook-ups. I tried plugging the RCA connectors into the Aux connection on my Sony reciever, but even if I switch the two plugs I don't get any sound from the table. I can hear the music from the cartridge if I put my ear up to it, but nothing from the reciever....


I can't find any info online, and the B&O website lists nothing of their turntables. Please Help.
 

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You need a receiver that has a specific "phono" input or you need to buy a phono preamp. Phono cartridges output a signal that is far too low for an amp to amplify all by itself. A good phono preamp will cost you a few hundred dollars, though I am sure you can get a cheapie at RatShack or similar.


The third wire is the ground wire. If (after you get the phono preamp or another receiver) you get a 60Hz hum, you'll need to ground the wire to either a groundpoint on the receiver or somewhere else that goes to ground.


BTW, thank you for making me feel old the DAY BEFORE MY 40TH BIRTHDAY!


;)



Bill
 

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Discussion Starter · #3 ·
Sorry Bill. Do most recievers have a phono input?? I thought my Sony POS did... But I guess not. Anyways, how about more up-to-date turntables? I'm not going to spend more than $20 on a phono preamp when the darn thing only cost $40 ($25+$15 S&H). I'll check out radioshack, but this isn't looking good. And I went out and bought a bunch of records tonight too....
 

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Most albums after about 1960 or so are stereo.

Back is the ole' days, receivers had 'phono' inputs. Since the 90's most preamps and receivers stop providing that input, and only have line level inputs. So most preamps or recievers require you to have a preamp between the cartridge and preamp. This preamp needs to amplify the low level signal from the cartridge, and apply RIAA equilization. Additionally there are two types of cartridges: moving coil and moving magnet. Moving coil are considered better, but require a different preamp.
 

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Discussion Starter · #5 ·
So how do I determine what kind of preamp i need, and where can IO get one cheap? Or should I just buy a more recent turntable? (and spend even more, just to play records)
 

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I take it you don't have an older reciver with a phono in lying around? How about your parents/friends? You could probably find one for free if you have a packrat family member.
 

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The age of the turntable doesn't have anything to do with it. Even a brand new $8000 table will need a phono stage. Receivers and preamps have not had phono stages since CDs ate the world back in the mid-to-late-80s. The phono stage is responsible for several things.


First, it is a pre-preamplifier, which needs to amplify the tiny millivolt-level signal to the sort of line stage single that comes out of a tuner or CD player. The gain associated with a regular preamp or preamp stage of a receiver is around 26 dB - phono stages are usually 40-65 dB, so it's quite a bit of gain.


Second, and perhaps even more important, the phono stage is responsible for adapting the signal to the RIAA equalization curve. In the process of packing the most music onto an LP, the signals are not encoded at the same level. Bass is usually compressed some, so that it takes physically less space worth of vinyl spirals. Even if you had enough gain in the preamp to be able to hear it without a phono stage, you'd have weird sound due to the lack of RIAA equalization.


Finally, moving coil cartridges are even lower output than most garden-variety moving magnet cartridges. Sometimes you will see a turntable connected to a "head amp" that steps up the moving-coil output; that feeds into a phono stage that steps up the signal to line stage and implements RIAA equalization; and that feeds into a preamp or receiver.


As far as "spend even more just to play records" - LPs are actually higher-resolution music than CDs, and sometimes by quite a bit. The least expensive phono stages I can think of are one from Rotel that's around $85 and an odd one from Hagerman that's $125. The Hagerman Bugle is mind-blowingly good for $125 - it's as good as some of the $600 phono stages I've heard.
 

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A more recent turntable will not have a phone preamp built into it. I have a fairly new VPI HW19 Jr. You'll have to break down and get yourself a phono preamp. I found a Pro-Ject phono preamp at AudioAdvisor for $119. The Pro-Ject preamp can accomidate both MM and MC cartridges. Personally, I would spend a little bit of money to get a good phono preamp. To me every dollar spent on a good vinyl setup provides much better performance than many digital gear costing more. You should also figure out how old that cartridge is on your B&O. Cartridges have a limited life. Either the stylus wears out from use (or abuse) or the rubber suspension for the needle becomes dry and brittle. So I would look to replacing the cartridge too.
 

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Discussion Starter · #9 ·
Ok- a couple more questions....


Radioshack and Ebay both have phono preamps for about $20-30 shipped. I know it's not a $125 Hagerman Bugle, but will it allow my reciever to pick up the signal? I'm not looking for a high end solution- I just decided to get a turntable on a whim and will only use it to play old records like once every 6 months.


Also, if/ when I eventually get a higher end reciever like a Pioneer 55txi or Denon 3803, will the phono inputs of those revievers be sufficient enough by themselves?




-Another thought- I did see that Denon has a turntable for about $125 shipped that has a line level output that can be hooked up to a reciever. The cartridge would also be brand new then too. This is more than I want to spend, but is it a valid option in liew of spending $120 on a preamp for an old turntable that is of unknown condition? (It looks ok, but who knows how old the cartridge or stylus is, and I'm NOT spending $100+ just for a B&O cart.)
 

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Yeah, the one from Ratshack will work. The only caveat is if the cartridge currently installed on your B&O is a MM cartridge. The Ratshack phono pre is only for MM cartridges. If you have a MC cartridge you may still be able to get it to work but the output signal from the MC cartridge may cause you to crank up the volume to compensate.


I also saw the Denon turntable you mentioned on their website. Looks like it does come with a phono pre. So I guess we're wrong about any tables not having a built in phono pre.
 

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Discussion Starter · #12 ·
A couple of things bother me about that model- it doesn't list RIAA equalization (is that something all of them do, or is it a specific and necessary item), and it runs off of a 9V battery. Have you used this preamp Tom?


I found this one on Ebay. It specifically lists RIAA eq, and uses a power cord so no changing batteries. The 60 db S/N seems low.... but is that a major factor in something like this?


What do you think?
 

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You can always just get a mixer (which is actually more usefull for 2 turntables). A good mixer can be as little as $30 (I suggest Numark or Technics). Even if you don't have another turntable, its fun to mess around with the faders, and EQ mixers.
 

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Discussion Starter · #15 ·
Just to sort of update those who have helped me... I got the Memorex preamp form CC just to test that my turntable does indeed work. I hooked it up and I got nothing. I turned up the volume on my reciever to the max, and with all of the mild hiss, I could BARELY hear the music. So I don't think this turntable will be working for me any time soon. So I guess I'm going to buy new now. Anyone know where to get a good deal? I don't want to spend much- if any- over $100. I wanted this to be a cheap $30 or so project for fun (like when I bought a tape deck component for my stereo).


Again- thanks for the help.
 

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Quote:
Originally posted by BigguyZ
Just to sort of update those who have helped me... I got the Memorex preamp form CC just to test that my turntable does indeed work. I hooked it up and I got nothing. I turned up the volume on my reciever to the max, and with all of the mild hiss, I could BARELY hear the music. So I don't think this turntable will be working for me any time soon. So I guess I'm going to buy new now. Anyone know where to get a good deal? I don't want to spend much- if any- over $100. I wanted this to be a cheap $30 or so project for fun (like when I bought a tape deck component for my stereo).


Again- thanks for the help.
Part of a turntable

Platter: the part that goes round and round

Tonearm: the arm that holds the cartridge and stylus, and keeps the needle in the grove

Cartridge: the part attached to the end of the tone arm that converts mechanical energy into electrical energy

Stylus: the needle that goes into the groove

Drive: the motor


If the platter goes around, and the tonearm goes up and down and pivots freely, the turntable works.


The only part that can cause a complete lack of sound is a bad cartridge, or broken wires from the cartridge to the preamp. Likely the cartridge is bad, but check the wiring. I doubt you will find a new turntable, with a cartridge for $100. Prices on turntables have greatly increased since their hayday.


SM
 

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The phono cables of that era were prone to failure, both the ones in the tonearm, (Broken Litz wire, corrosion at headshell), and the cables going to the receiver. (Quick cable guide- brown and white- British, horrible, yuch, yuch. Throw away. Gray and Black- old aftermarket replacements, usually Recotron; not bad. Red and yellow- aftermarket, fairly recent, but not necessarily any good for phono applications (Capacitance too high). The early B&O turntables _usually_ had a DIN plug on their cables, or rather cable, rather than phono plugs, to match the DIN input of their receivers. They sold a short DIN to phono adapter (Red and yellow) for non-DIN receivers.

Many higher end tables, like the B&O, also have an audio-disconnect switch to prevent noise when the tonearm is travelling, and these can corrode as well. One slightly more remote possibility is that the magnets in the cartridge,stylus are shot; I've only seen this _once_, but replacing the cartridge guarantees that you get a new stylus as well.


These are all simple problems to fix, if you have any techie genes, but irritating to troubleshoot if you don't.


B&O catches some flak for the low audio output of their receivers, and modest performance of their speakers, for the price asked, but I always found their turntables to be first rate. Every one that I've ever seen has had a proprietary moving magnet cartridge.


GoodGuys.com have a Denon DP29F semiautomatic belt drive turntable package with cartridge and RIAA equalized amp for $150. Search the site, if you don't have a local store. Not bad, and I've seen other models in the local store for under $100.
 

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Best Buy sells a Sony model with a built in Pre-amp for under $100 I believe. You just flip a switch to turn on the preamp, plug the RCA cables into an aux. input on the receiver, and put on some vinyl. It is not the greatest turntable in the world, but it very passable if you are just wanting to get into vinyl without spending a fortune. I have one and it has worked very well. If you decide to get more into vinyl, then you can buy a better table and use the Sony as a backup or put it in a bedroom or somewhere, which is what I'm doing.
 

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Discussion Starter · #19 ·
I think for now that I'm going to disect the turntable and see if I can find any loose wires and such. Maybe it's just a minor wiring problem. I do plan on getting a higher end reciever somewhat soon (within next 6 months), so I'll wait to buy a new turntable until I see if that reciever's phono input will get it to work. If I can't fix it- at that time I'll maybe get a Denon DP-29F. Should be better than a Sony, and I know it'll be supported more (The B&O website doesn't list turntables at all). For now I have a TON of things I want to spend money of before I dump $100+ into vinyl. So thanks for all your help, but I'm done with this thing for now.
 

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Z, start with the 4 tiny (and fragile!) wires on the rear of the cartridge. Remove and replace each one (while disconnected from the preamp!). If there are none (P-mount), the remove the cartridge from the tonearm (rotate the locking sleeve) and clean the pins (fragile again!) and contact pads with a pencil eraser.


Also, make sure you hooked the preamp up correctly. I don't mean to insult, but it's easy to mix up the ins and outs. And make sure you selected the right input, and didn't have the tape (monitor) input selected, unless that's the one you used.
 
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